Calcium Carbonate Reactions
Calcium Carbonate Reactions is what happens when an acid like vinegar meets a calcium carbonate surface like an eggshell, dissolving it and producing bubbles.
When vinegar splashes onto baking soda in a bowl, tiny bubbles form and foam rises up. The vinegar breaks apart the baking soda and releases carbon dioxide gas — that is the bubbling you see. Calcium carbonate in an eggshell reacts the same way when acid touches it. The acid pulls the shell apart piece by piece, and gas bubbles escape as the surface dissolves.
Explaining calcium carbonate reactions by grade level
When you put an egg in vinegar, tiny bubbles form on the shell. The vinegar slowly eats away at the hard shell over a day or two. If you leave it long enough, the shell disappears completely. The egg feels soft and rubbery because the hard outer layer is gone. The bubbles are a gas escaping as the shell breaks down.